Et tu, Southwest? A relative absence of fees and an overall nonelitist, democratic approach to airline travel are among the reasons Southwest Airlines has been so successful. A new fee — $40 to be among the first on the plane — could cancel out some of the goodwill built up by the carrier over the years.

By now, flyers probably shouldn’t be surprised by any new airline fee. These fees hit a record high last year (after hitting a record high the year before that), and what with the regular release of new fees — excuse me, “enhancements,” to use American Airlines’ Big Brother–like marketing lingo — it’s likely even more fees will be collected by carriers this year.

Even so, the perception has been that Southwest Airlines was different. While nearly every carrier has added fees for checked baggage (and sometimes for carry-on luggage as well), Southwest has pumped up its complimentary service with a ubiquitous “Bags Fly Free” ad campaign. The airline’s generous baggage policies have regularly helped put Southwest among the top customer-rated airlines in the U.S.

Southwest’s approach to seating has also set it apart from the crowd. Southwest doesn’t have reserved seating. Instead, passengers pick out seats when they board, according to a specified boarding order. Some flyers love the system; for others, it drives them batty with anxiety that they’ll be stuck in the worst seat on the plane. Love or hate the system, though, most found it to be (mostly) democratic and (mostly) fair — and at least more reasonable than the airlines adding fees for seat reservations.

Slowly, however, Southwest seems to be embracing the approach of other airlines, in that clearly better service goes to customers who pay for it. For years, Southwest has offered an Early Bird Check-in: for $10 each way, passengers were ensured they’d be in the first or second boarding group, meaning they would have a decent selection of empty seats to choose from.

Now Southwest is adding another tier for boarding privileges. The airline once celebrated for selling flights for $40 (and sometimes less than that) just launched a $40 fee for passengers who want to be guaranteed they’ll be in the first boarding group. Customers can pay the fee 45 minutes before the flight, if the section isn’t already sold out.

Many frequent flyers aren’t happy with the new fee. At SmarterTravel, travel-rewards expert Tim Winship wrote:

There’s no benchmark against which the new fee can be measured and evaluated, but charging $40 just to get an earlier start in Southwest’s first-come-first-served boarding scrum seems cruelly unreasonable. That assessment will be reality-tested as travelers vote with their wallets.

On the one hand, the new fee should seem like no big deal. No one is forcing passengers to pay it. Anyone who doesn’t think it’s worth the cost can elect to skip it. On the other hand, what this and most airline fees essentially do is screw over travelers who don’t pay up. The introduction of fees for basic services and perks that used to be free obviously decreases the likelihood of travelers getting those basic services and perks for free anymore. Passengers who don’t pay can expect worse treatment, as simple services — like getting a fair shot at a decent seat on the plane — are now viewed as revenue streams, as perks saved for the elite.

I flew Southwest the day or so after they announced the new $40 upgraded boarding fee. While I was waiting for my flight to board they REPEATEDLY announced the new option over the PA system. And I do mean REPEATEDLY. I don't think there were many takers.